The last two BioShocks took place in the gloom of leaky undersea dystopia, Rapture. This one's set in Columbia, a shining steampunk city in the clouds, where evil messianic Father Comstock has imprisoned Elizabeth, a girl with strange powers. Naturally, you're there to perform the jail break. As well as all the sunshine and open space, this differs from past outings in that Columbia isn't derelict; it's well populated, complete with a police force and military to foil your plans. The game's alternate realities, invoked in your attempts to escape, cause added destruction; while gunfights are fast and dangerous, with a fine balance between guns and vigors, the game's version of magic. The plot, with its shifting timelines and themes of religious zealotry and racism, also has a wonderfully twisted conclusion; it's potent, compelling and fun.